Load weight indicator for cranes



July 21, 1953 c. L. WETSEL. 2,646,273

LOAD WEIGHT INDICATOR FOR CRANES Filed Oct 21, 1949 2 Sheets-Sheet l W 4 CeciZLlUefseZ Mi. Mi

ATTORNEYS July 21, 1953 c. L. WETSEL LOAD WEIGHT INDICATOR FOR CRANES 2 Sheets-Sheet 2 Filed 001;. 21, 1949 C'ecil .L. weisel fiT gl Patented July 21, 1953 etsel, Sacramento,

Applicationijctbberm, 19i9, jser'iar-No; 122,740 Q1 ,j a

'This invention is directed 'to; and'it is an object to provide, a novel device for indicatingthe weight of a load suspended from a crane; 'the invention being especially-designed, butnot limited, for use on a truck loading crane whereby theload placed on the truck is known and can be limited to the amount-specifie'din safety-and motor vehicle codes.-

'- w Another object of the invention is to provide a load- -weightindicator ior cranes of the type which has a poweractuated lift cable subjected tothe weight oi the susp'ended load; the device including a tension responsive unit cooperating with the cable without interfering with normal lengthwisemotion thereof, and an indicator connected to such unit operative to reflect load imposed tension on the cableintermsof weight.

A further object cf 'the invention isto provide a load weight indicator for cranes, as in the pre ceding paragraph, wherein the tension responsive unit creates fluid pressure proportionate to the load; said indicator being afluid-pressure gauge connected to said unit and. calibrated'in terms of weight. This weight indicating gauge is mounted in a position within view of the crane operator.

An additional objectoftheinvention is to pro-- vide-a load weight indicator for cranes, which is simple in construction, being designed 'for" ease and economy of manufacture.

It is also an object of the invention to provide a load weight indicator for cranes, which is of sturdy construction and arranged in a manner so that it is not subject to any substantial wear and tear during normal operation of the crane.

A further object of the invention is to provide a practical and reliable load weight indicator, and one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claim.

In the drawings:

Fig. 1 is a side elevation of a portable industrial crane embodying the invention.

Fig. 2 is a similar view, but shows an alternate mounting of the fluid pressure creating unit.

Fig. 3 is an enlarged sectional elevation of the fluid pressure creating unit.

Fig. 4 is an enlarged face view of the fluid pressure gauge as calibrated in terms of weight.

Referring now more particularly to the characters of reference on the drawings, and at present to Figs. 1, 3, and e, the invention is here shown .1 Claim. (c1. 265:4?)

as embodied ina portable industrial' 'crane which i-nclude's a-track-supported body ihaving a :for-

wardly projecting boom 2 pivoted; as-at-3;to the body for vertical adjustment; such boom being controlled by a cablesystem [which-leads rear wardly to awinch-(not shown) in the cabdot the cranes Additionally, the "crane includes a lift cable 5 which extendsalongthe boom 2 frorn a winch i in the "cab 5'; i said "winch ltogetlier with tlie winch which controls the cable systemfi-bei'ng under the selective control ofthe-operatorfl- Intermediate its ends the lift cable "6' turns 'over, and depends from, an outer end sheave 8 0p. -the boom '2. The depending reach-'9 of the lift cable't is adapted to beconnected, as by a hook and suspension'cable assembly iitwi-th the'load, hereshown as alog'lI.

' At a pointinte'rmediatetheends' oftheboom 2, the latter is fitted with a tensionrespon'sive, fluid pressure creating unit, indicated generally "Apair of spaced; direction-changing pulleys it are mounted on the boom "2 lengthwiseftherec'f and with the fluid pressure creating unit' i centrally 'therebetween;

Such fluid pressure creating unit' 12 includes a laterally offset pulley I' l which engages the porftion of the cable betweenthe pulleys i3 and deflectssaid portion laterallyout of its normal "line of pull; the lift cable passing under both of the pulleys l3 and over the pulley 14. The result is that the pulley I4 is urged inwardly toward such normal line of pull when a load is imposed on the lift cable 6.

The pulley M is journaled by a shaft i5 in a yoke 16 secured to the outer end of, an inwardly projecting plunger H which slidably engages in a neck Hi; there being a protective cap IS on the outer end of the plunger i'i encompassing the corresponding end of said neck IS.

The neck I8 is formed axially on one end of a short but relatively large-diameter cylinder 26 which includes a base 2| afiixed to the boom 2.

At its inner end the plunger ii is secured to a piston 22 which works in the cylinder 20; there being a quantity of fluid 23, preferably oil, in the cylinder 20 between the piston 22 and base 2|.

A conduit 24 leads from the fluid chamber of the cylinder 20 rearwardly into the cab 5 of the crane; there being a flexible portion 25 in the conduit 24 between the boom 2 and cab 5 whereby the boom may work without interfering with the conduit arrangement. The conduit 24 includes a hand valve 26 which is normally open.

Within the cab 5 the conduit 24 connects to a fluid pressure gauge 21 calibrated in terms of weight. See Fig. 4.

When the crane is in use with a load, such as a log ll, suspended by the depending reach 9 of the lift cable 6, a tension is imposed on said cable by the load and such tension in turn acts to urge the pulley l4, plunger H, and piston 22 inwardly. When this occurs the piston 22 exerts a proportionate pressure on the fluid 23, which pressure delivers through the conduit 24 to the gauge 27, where it is read in terms of weight. The calibration of the the gauge 27 is such that it reads ac curately with respect to the suspended weight of the load. Thus, as each load is lifted by the crane, the operator can readily ascertain its weight, and if desired make a record thereof.

The device is extremely advantageous for many uses, as for example the loading of logging trucks wherein the truck must not be overloaded; i. e.

the load must satisfy certain safety and motor vehicle regulations with respect to the maximum Weight of such load.

With the present invention the crane operator can ascertain the weight of each part of the load as it it placed on the truck and readily compute the total.

It is also contemplated that the gauge 27 may be arranged so that it is of a cumulative type;

i. e. to reflect the total Weight of several load parts successively lifted by the crane.

In Fig. 2' the fluid pressure creating unit is indicated at 28, being of exactly the same construction as the unit l2, but mounted closely adjacent the free end of the boom; 1. e. very close to the outer end sheave 29. Here the lift cable 30 runs directly from the outer end sheave 29 over the cable deflecting pulley 3| of the unit 28, and thence extends inwardly to pass under a direction control pulley 32.

With this arrangement one less pulley is required than in the embodiment of Fig. 1, although the fluid presure conduit 33 must be elongated, extending from the fluid pressure creating unit 28 for substantially the full length of the boom, and thence traversing into the cab for connection to the gauge 34.

The device, in this embodiment, Works in exactly the same manner as heretofore described.

The load weight indicator in either of its embodiments provides a very practical, reliable, and convenient device for the indication, automatically, of each load lifted by the crane.

From the foregoing description it will be readily seen that there has been produced such a device as substantially fulfills the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claim.

Having thus described the invention, the following is claimed as new and useful, and upon which Letters Patent are desired:

A load-weight indicator for a crane, said crane including a boom, a sheave at the outer end of the boom and a lift cable extending along the boom to and depending about the sheave; the indicator comprising, in combination with said sheave, a pulley on the boom relatively close to but spaced along the boom from the sheave and under which the cable passes, a fluid pressure unit mounted on the boom between the pulley and sheave and including a fluid contacting plunger movable laterally of the cable and a pulley on the plunger engaging and deflecting the cable from a normal straight line of pull between the first named pulley and the sheave; increased tension on the cable acting to shift the plunger in a direction to increase the fluid pressure in the unit, there being a weight indicating gauge actuated by such pressure increase.

CECIL L. WETSEL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,779,656 Brauer Oct. 28, 1930 1,780,238 Lincoln Nov. 4, 1930 1,872,087 Martin Aug. 16, 1932 2,030,529 Nash Feb. 11, 1936 2,324,769 Davis July 20, 1943 2,488,070 Spalding Nov. 15, 1949 FOREIGN PATENTS Number Country Date 311,714 England May 15, 1929 

